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Довольно интересная статья о нашем чувстве справедливости и важности выгоды при решении простых экономических задач. У этой статьи есть еще вторая часть, но получается слишком длинно, поэтому кто хочет - пришлю по email.
THE ECONOMICS FAIR PLAY
Why do we value fairness and cooperation over seemingly more rational selfishness? How can Darwinian generosity arise?
Biologists and economists explain
By Karl Sigmund, Ernst Fehr and Martin A. Nowak
Copyright 2001 Scientific American, Inc.
Imagine that somebody offers you $100. All you have to do is agree with some other anonymous person on how to share the sum. The rules are strict.
The two of you are in separate rooms and cannot exchange information. A coin toss decides which of you will propose how to share the money. Suppose that you are the proposer. You can make a single offer of how to split the sum, and the other person-the responder- can say yes or no. The responder also knows the rules and the total amount of money at stake. If her answer is yes, the deal goes ahead. If her answer is no, neither of you gets anything. In both cases, the game is over and will not be repeated. What will you do?
Instinctively, many people feel they should offer 50 percent, because such a division is "fair" and therefore likely to be accepted. More daring people, however, think they might get away with offering somewhat less than half of the sum. Before making a decision, you should ask yourself what you would do if you were the responder. The only thing you can do as the responder is say yes or no to a given amount of money. If the offer were 10 percent, would you take $10 and let someone walk away with $90, or would you rather have nothing at all? What if the offer were only 1 percent? Isn't $1 better than no dollars? And remember, haggling is strictly forbidden. Just one offer by the proposer: the responder can take it or leave it. So what will you offer? You may not be surprised to learn that two thirds of offers are between 40 and 50 percent. Only four in 100 people offer less than 20 percent. Proposing such a small amount is risky, because it might be rejected. More than half of all responders reject offers that are less than 20 percent. But here is the puzzle: Why should anyone reject an offer as "too small"? The responder has just two choices: take what is offered or receive nothing. The only rational option for a selfish individual is to accept any offer. Even $1 is better than nothing. A selfish proposer who is sure that the responder is also selfish will therefore make the smallest possible offer and keep the rest. This game-theory analysis, which assumes that people are selfish and rational, tells you that the proposer should offer the smallest possible share and the responder should accept it. But this is not how most people play the game.
The scenario just described, called the Ultimatum Game, belongs to a small but rapidly expanding field called experimental economics. A major part of economic theory deals with large-scale phenomena such as stock market fluctuations or gross national products. Yet economists are also increasingly fascinated by the most down-to-earth interactions-the sharing and helping that goes on within office pools, households, families and groups of children. How does economic exchange work in the absence of explicit contracts and regulatory institutions? For a long time, theoretical economists postulated a being called Homo
economicus-a rational individual relentlessly bent on maximizing a purely selfish reward. But the lesson from the Ultimatum Game and similar experiments is that real people are a crossbreed of H. economicus and H. emoticus, a complicated hybrid species that can be ruled as much by emotion as by cold logic and selfishness. An interesting challenge is to understand how Darwinian evolution would produce creatures
instilled with emotions and behaviors that do not immediately seem geared toward reaping the greatest benefit for individuals or their genes. Werner Guth of Humboldt University in Berlin devised the Ultimatum Game some 20 years ago. Experimenters subsequently studied it intensively in many places using diverse sums. The results proved remarkably robust. Behavior in the game did not appreciably depend on
the players' sex, age, schooling or numeracy. Moreover, the amount of money involved had surprisingly little effect on results. In Indonesia, for instance, the sum to be shared was as much as three times the subjects' average monthly income- and still people indignantly refused offers that they deemed too small. Yet the range of players remained limited in some respects, because the studies primarily involved people in more developed countries, such as Western nations, China and Japan, and very often university students, at that.
Recently an ambitious cross-cultural study in 15 small-scale societies on four continents showed that there were, after all, sizable differences in the way some people play the Ultimatum Game. Within the achiguenga tribe in the Amazon, the mean offer was considerably lower than in typical Western-type civilizations- 26 instead of 45 percent. Conversely, many members of the Au tribe in Papua New Guinea offered more than half the pie. Cultural traditions in gift giving, and the strong obligations that result from accepting a gift, play a major role among some tribes, such as the Au. Indeed, the Au tended to reject excessively
generous offers as well as miserly ones. Yet despite these cultural variations, the outcome was always far from what rational analysis would dictate for selfish players. In striking contrast to what selfish income maximizers ought to do, most people all over the world place a high value on fair outcomes. Numerous situations in everyday life involve trade-offs between selfishness and fair play. A colleague, for example,
invites you to collaborate on a project. You will be happy to do it, if you expect a fair return on your investment of time and energy or if he has helped you in the past. The pure Ultimatum Game, however, has artificial constraints that rarely apply in real-life interactions: haggling is impossible, people do not get to know each other, the prize vanishes if not split on the first attempt and the game is never repeated. But such constraints, rather than being a drawback, let us study human behavior in well-de- fined situations, to uncover the fundamental principles governing our decision- making mechanisms. The process is somewhat like physicists colliding particles in a vacuum to study their properties.
ECONOMISTS have explored a lot of variations of the Ultimatum Game to find what causes the emotional behavior it elicits. If, for instance, the proposer is chosen not by a flip of a coin but by better performance on a quiz, then offers are routinely a bit lower and get accepted more easily-the inequality is felt to be justified. If the proposer's offer is chosen by a computer, responders are willing to accept considerably less money. And if several responders compete to become the one to accept a single proposer's offer, the proposer can get away with offering a small amount. These variations all point to one conclusion: in pairwise encounters, we do not adopt a purely self-centered view- point but take account of our co-player's outlook. We are not interested solely in our own payoff but compare ourselves with the other party and demand fair play. Why do we place such a high value on fairness that we reject 20 percent of a large sum solely because the co-player gets away with four times as much? Opinions are divided. Some game theorists believe that subjects fail to grasp that they will interact only once. Accordingly, the players see the offer, or its rejection, simply as the first stage of an incipient bargaining process. Haggling about one's share of a resource must surely have been a recurrent theme for our ancestors. But can it be so hard to realize that the Ultimatum Game is a one-shot interaction? Evidence from several other games indicates that experimental subjects are cognitively well aware of the difference between oneshot and repeated encounters. Others have explained our insistence on a fair division by citing the need, for our ancestors, to be sheltered by a strong group. Groups of hunter-gatherers depended for survival on the skills and strengths of their members. It does not help to outcompete your rival to the point where you can no longer depend on him or her in your contests with other groups. But this argument can at best explain why proposers offer large amounts, not why responders reject low offers. Two of us (Nowak and Sigmund) and Karen M. Page of the Institute for Advanced Study in Princeton, N.J., have recently studied an evolutionary model that suggests an answer: our emotional apparatus has been shaped by millions of years of living in small groups, where it is hard to keep secrets. Our emotions are thus not finely tuned to interactions occurring under strict anonymity. We expect that our friends, colleagues and neighbors will notice our decisions. If others know that I am content with a small share, they are likely to make me low offers; if I am known to become angry when facing a low offer and to reject the deal, others have an incentive to make me high offers. Consequently, evolution should have favored emotional responses to low offers. Because one-shot interactions were rare during human evolution, these emotions do not discriminate between one-shot and repeated interactions. This is probably an important reason why many of us respond emotionally to low offers in the Ultimatum Game. We may feel that we must reject a dismal offer in order to keep our self-esteem. From an evolutionary viewpoint, this self-esteem is an internal device for acquiring a reputation, which is beneficial in future encounters. The Ultimatum Game, in its stark simplicity, is a prime example of the type of games used by experimental economists: highly abstract, sometimes contrived interactions between independent decision makers. The founders of game theory, the Hungarian mathematician John von Neumann (one of the fathers of the computer) and the Austrian economist Oskar Morgenstern, collaborating in Princeton in the 1940s, used parlor games such as poker and chess for illustrating their ideas. Parlor games can certainly be viewed as abstractions of social or economic interactions, but most of these games are zero-sum: the gains of one player are the losses of another. In contrast, most real-life economic interactions
are mixed-motive: they display elements of cooperation as well as competition. So-called Public Goods games model that situation.